Disposable absorbent article with flushable insert

ABSTRACT

A disposable article, such as a diaper, for absorbing and containing urine and other body exudates has an absorbent insert pad that may be flushed in a toilet. The article preferably includes a backing sheet and a bodyside liner that are substantially coterminous. In one embodiment of the invention, a secondary absorbent body, which is disposed between the backing sheet and the bodyside liner, has a pocket formed therein. The absorbent insert pad is positioned against the bodyside liner and located generally within the pocket. A cover is releasably attached to the bodyside liner to maintain the insert pad within the pocket.

This is a continuation application of application Ser. No. 08/268,862filed on Jun. 29, 1994 now U.S. Pat. No. 5,405,342; which is acontinuation of application Ser. No. 08/188,626, filed on Jan. 27, 1994,now abandoned; which is a continuation of application Ser. No.08/116,822, filed on Sep. 3, 1993, now abandoned; which is acontinuation of application Ser. No. 07/816,457, filed on Dec. 31, 1991,now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of disposablearticles utilized for absorption and containment of urine and other bodyexudates. More particularly, the invention relates to a disposablearticle, for example a diaper, that incorporates components such as anabsorbent insert pad which may be removed from the article and flusheddown a toilet.

Disposable articles for the absorption and containment of urine andother body exudates are generally known in the art. Such disposablearticles have found particular utility in the fields of infant care,child care, feminine care, and adult incontinency. Present commerciallyavailable disposable articles for such uses are generally unitary,preshaped or prefolded, and comprised of a fluid pervious bodysideliner, a fluid impervious backing sheet, and an absorbent materialdisposed between the bodyside liner and the backing sheet. Disposablearticles of this type effectively and efficiently absorb and containurine or other body exudates. Such articles are designed for a singleuse and are simply deposited after use in a waste receptacle. This easeand convenience of disposal has contributed to the increasing popularityof such disposable absorbent articles.

Until now, the vast majority of the absorbent articles of :heaforementioned type have been designed to be disposed of by delivery tosolid waste landfills. Such absorbent articles have not generally beencompatible with being flushed down a toilet. The relatively few productsthat have been designed specifically to be disposed of, at leastpartially, by flushing have been ineffective or impractical.

With regard to diapers, for example, U.S. Pat. No. 3,211,147 to P. O.Pherson et al. discloses a diaper pad that is intended to be completelydisposed of in household toilets and septic tanks. The pad includes apaper web, several fluff pads, and paper reinforcing strips. The diaperemploys numerous channels to distribute fluids. Because the pad containsonly wood pulp derivatives, the user may separate the diaper into piecesand flush the pieces in a toilet.

A diaper with a flushable portion is disclosed in U.S. Pat. No.3,667,466 to H. J. Ralph. This patent discloses a diaper having aflushable layer and a reusable retainer. The flushable layer is composedof top and bottom layers of wet-strength material that surround anabsorbent layer. The diaper incorporates numerous perforations whichcause the diaper to be self-segmenting and self-disintegrating whenimmersed in a toilet.

Another diaper with a flushable portion is disclosed in U.S. Pat. No.4,964,857 to C. Osborn. This patent discloses a diaper that incorporatesa removable and flushable inner sheet of material. The inner sheet has aliquid permeable layer, an absorbent layer, and a moisture repellentlayer. The inner sheet, which is attached to the remainder of the diaperby adhesives, is constructed with a plurality of perforations and aseries of hollow channels. A drawstring located within the channels isused to remove the inner sheet from the remainder of the diaper.

These attempts to provide diapers that are completely or partiallyflushable have not been entirely successful. For example, theabove-mentioned completely flushable diapers must necessarily be limitedto materials that can be flushed. Consequently, completely flushablediapers have provided less than desirable fit and absorbencycharacteristics. On the other hand, the diapers having a flushable layerand a reusable retainer are frequently messy and inconvenient. Finally,the diapers that incorporate a removable insert have not effectivelyutilized the absorbent material contained within the insert and havetended to prematurely experience saturation spots. Consequently, thesediapers have not provided an adequate amount of comfort and dryness.Additionally, these diapers have included devices such as drawstrings toremove the inserts. Devices of this type present numerous manufacturingdifficulties and increase the expense and complexity of production.

The present invention teaches an improved disposable article whichprovides components, such as an absorbent insert pad, which may bequickly and conveniently removed from the article. The user can disposeof the insert pad, as well as any solid feces material held in thearticle, in any toilet that is connected to a holding tank, a municipalsewer, or other municipal wastewater treatment system. The insert padmay then be flushed down the toilet, and the remainder of the articlemay be composted or recycled where suitably equipped facilities areavailable, disposed at a conventional landfill site, or incinerated.Alternately, the complete absorbent article including the insert pad maybe directed into the solid waste stream. Thus, the user may select amongseveral alternative disposal methods, thereby accommodating theindividual's preferences and the community's capabilities.

SUMMARY OF THE INVENTION

The present invention was developed in order to remedy thepreviously-mentioned drawbacks associated with present disposableabsorbent articles comprising portions that are intended to be flusheddown a toilet. It was also developed to allow users of disposableabsorbent articles to select among several disposal options, based upontheir particular preferences and circumstances. An absorbent articleaccording to the present invention includes a shell with a top surfaceand an opposite bottom surface. The shell defines a front waist section,a back waist section, and opposed first and second sides extendingbetween the front and back waist sections. A pair of containment flapsare positioned inboard of the respective first and second sides andextend between the front and back waist sections. An insert pad of thearticle is formed of flushable absorbent material and positioned againstthe top surface of the shell, between the containment flaps. The insertpad is releasably maintained against the top surface of the shell. Thus,this aspect of the invention gives the user a convenient option todisposing of the article at a conventional landfill site. The absorbentinsert pad, as well as the firm fecal waste from the article, can beeasily removed from the article and disposed of in a toilet. The insertpad is formed of materials that will disperse in water in conjunctionwith the hydraulic action of the toilet and the transportation system enroute to the treatment facility. In this way, the user has the option ofdirecting the solid fecal waste and a significant portion of theabsorbent article to a wastewater treatment facility, rather than to alandfill.

In another aspect of the invention, the absorbent article includes asecondary absorbent body disposed between top and bottom surfaces of ashell. The secondary absorbent body is formed with a pocket. An insertpad is formed of a flushable absorbent material and sized to fitgenerally within the pocket. The insert pad is positioned against thetop surface and releasably maintained within the pocket. This aspect ofthe invention enhances the leakage protection of the article. The insertpad functions as the initial and primary absorbent of the article. Thesecondary absorbent body laterally surrounds the insert pad and absorbsliquids which may migrate from the crotch of the article toward theedges of the article.

In another aspect, the absorbent article of the present inventionincludes a backing sheet and a bodyside liner that define a front waistsection, a back waist section, and sides therebetween. A pair ofcontainment flaps extend between front and back waist sections of thearticle and are positioned inward of the sides. A secondary absorbentbody formed with a pocket is disposed between the backing sheet and thebodyside liner, and an insert pad is releasably maintained on the topsurface between the containment flaps. This aspect also results in anabsorbent article with improved leakage-resistance. The containmentflaps retard the movement of solid fecal material, urine, and fluidicfecal material away from the insert pad. The effectiveness of the insertpad is thereby enhanced, which causes the vast majority of the fluidicwaste to be absorbed by the insert pad. Where the insert pad is disposedof in a toilet and subsequently flushed, the majority of the fluidicwaste of the user is directed to a wastewater treatment facility, ratherthan to a landfill.

In another aspect of the invention, the absorbent article includes ashell with a secondary absorbent body disposed between top and bottomsurfaces of the shell. A removable insert pad, formed of flushable,absorbent material, is positioned against the top surface and is insubstantially direct fluid contact with the secondary absorbent body.This aspect of the invention also enhances the leakage protection of thearticle. The insert pad functions as the initial and primary absorbentstructure of the article. Before any particular portion of the absorbentinsert pad becomes saturated, however, the secondary absorbent body isavailable to absorb urine and other fluidic material. The transport ofliquid from any particular portion of the absorbent insert pad to theunderlying secondary absorbent body is possible because the insert padand secondary body are in substantially direct fluid contact.Consequently, the insert pad tends not to experience prematuresaturation spots, and the top surface of the shell and the top of theinsert pad remain dry and comfortable for the wearer.

In yet another aspect, the invention includes a method for improveddisposal of body exudates, such as urine and solid fecal waste. Themethod includes providing an absorbent article with a shell and aremovable insert pad that is made of materials that separate in water.The shell includes a secondary absorbent body that includes a pocket.The insert pad is located on the shell and generally within the pocket.The method also includes arranging the absorbent article on the body ofa wearer in a position where the insert pad receives body exudates fromthe wearer, removing the insert pad and exudates from the absorbentarticle, and depositing them in a toilet. The insert pad and exudatesare then flushed down the toilet. This aspect of the invention resultsin solid and liquid waste from the article being disposed of in atoilet. This reduces the amount of non-flushable waste that the userneeds to store until it can be entered into the solid waste stream.Correspondingly, this also reduces the odor problems associated withtemporarily storing absorbent articles containing solid and liquid humanwaste.

As can be seen from the foregoing comments, it is an object of theinvention to provide an absorbent article that gives the user severaldisposal options by including a removable portion that can be flushed ina toilet. The removable, flushable portion disperses into fibers orparticles that can be accommodated by residential holding tanks ormunicipal sewers, or treated at municipal wastewater treatmentfacilities.

It is another object of the invention to provide a disposable absorbentarticle that facilitates a user's ability to dispose of solid fecalwaste in the toilet. The steps involved in removing the insert pad fromthe article provide a clean and convenient means for removing fecalwaste from the article. This beneficially reduces the amount ofodor-causing waste that must be stored in the user's residence.

It is another object of the invention to provide an absorbent articlethat incorporates a relatively thin, removable, flushable insert pad andconcurrently offers considerable leakage protection. The non-flushableportion of the article can be constructed of non-flushable materialsthat are particularly suited to enhance leakage protection.

It is a further object of the invention to provide an absorbent articleincorporating a flushable insert portion that can be removed from thearticle without exposing the user to the soiled portions of the article.

It is still another object of the invention to provide a disposablearticle having a non-flushable portion and a removable, flushableinsert, where the majority of the absorbent material of the article iscontained in the flushable insert.

The foregoing and other objects, features and advantages of the presentinvention will appear from the following description. In thedescription, reference is made to the accompanying drawings whichillustrate preferred embodiments of the invention. Such embodiments donot represent the full scope of the invention. Reference shouldtherefore be made to the claims herein for interpreting the full scopeof the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a disposable diaper, as an example of anabsorbent article according to the present invention.

FIG. 2 is an exploded perspective view showing several components of theabsorbent article of FIG. 1.

FIG. 3 is a top plan view of the absorbent article of FIG. 1, theabsorbent article being in a stretched condition.

FIG. 4 is an enlarged view in section taken generally from the plane ofthe line 4-4 of FIG. 1.

FIG. 5 is an enlarged view in section taken generally from the plane ofthe line 5-5 of FIG. 1.

FIG. 6 is a perspective view illustrating an initial step in thedisposal of an absorbent insert pad of the absorbent article of FIG. 1.

FIG. 7 is a perspective view illustrating a further step in the disposalof the absorbent insert pad of the absorbent article of FIG. 1.

FIG. 8 is a perspective view illustrating disposal of an absorbentinsert pad of a second embodiment of the present invention.

FIG. 9 is an exploded perspective view of a third embodiment of anabsorbent article according to the present invention.

FIG. 10 is an enlarged view in section, similar to FIG. 4, but relatingto the absorbent article of FIG. 9.

FIG. 11 is a perspective view illustrating disposal of an absorbentinsert pad of a fourth embodiment of the present invention.

FIG. 12 is an exploded perspective view of a fifth embodiment of anabsorbent article according to the present invention, with portionsbroken away for the purposes of illustration.

FIG. 13 is an enlarged view in section, similar to FIG. 4, but relatingto the absorbent article of FIG. 12, with several componentsdisproportionately enlarged for the purposes of illustration.

FIG. 14 is an exploded perspective view of a sixth embodiment of anabsorbent article according to the present invention.

FIG. 15 is an enlarged view in section, similar to FIG. 4, but relatingto the absorbent article of FIG. 14, with several componentsdisproportionately enlarged for the purposes of illustration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 and 2, a disposable absorbent article formedaccording to the invention is shown for purposes of illustration as adisposable diaper 20. The invention may also be incorporated, however,in absorbent articles such as adult incontinency garments, femininenapkins, children's training pants, or the like. The diaper 20 providesdisposal options principally because it includes an absorbent insert pad21 (FIG. 2) that may be discarded into a toilet that is operativelyconnected to a holding tank, a municipal sewer, or other types ofmunicipal wastewater treatment systems. The diaper 20 provides otherbenefits because it enhances a parent's ability to dispose human wastein the toilet.

When encountering the water in the toilet, the insert 21 partially orcompletely disintegrates into individual, flushable fibers. Uponflushing the insert pad 21 and any fecal waste, remainingundisintegrated portions of the pad 21 disperse due to hydraulic actionwhile exiting the bowl or en route to a municipal sewer or wastewatertreatment facility. Thus, a diaper 20 incorporating the presentinvention gives users the option of conveniently directing their child'sbodily waste, along with disintegrative and treatable portions of thediaper, to a wastewater treatment facility. The remaining portions ofthe diaper 20 that are not flushed are suitable for recycling,composting or solid waste disposal, according to the user's preferenceand the availability of appropriate facilities.

In general, a disposable diaper 20 incorporating the present inventionis formed of a non-flushable garment shell 22, a flushable absorbentinsert pad 21 positioned adjacent to and in contact with the shell, anda non-flushable cover 23 for releasably maintaining the insert pad inposition relative to the shell. It will be understood, however, thatpresently non-flushable components of the diaper, such as the cover 23,may also be formed of flushable materials.

The shell 22 preferably comprises a substantially liquid imperviousbacking sheet 24 and a substantially liquid pervious bodyside liner 25that are in facing relation and substantially coterminous. A secondaryabsorbent layer 26 (see FIGS. 3-5), discussed more fully below, isemployed in the illustrated embodiment and is disposed between thebacking sheet 24 and the bodyside liner 25.

More specifically, the backing sheet 24 may comprise a thin,substantially liquid impermeable web or sheet of plastic film such aspolyethylene, polypropylene, polyvinyl chloride or similar material. Thebacking sheet 24 may also be formed of a compostable material such as aweb or sheet of polyvinyl alcohol-based film. The backing sheet materialmay be transparent or opaque and have an embossed or matte surface. Onepreferred material for the backing sheet 24 is a polyethylene film thathas a nominal thickness of about 0.00125 inch and a systematic matteembossed pattern, and that has been corona treated on both sides.Alternately, the backing sheet 24 may comprise a nonwoven, fibrous webwhich has been suitably constructed and arranged to be substantiallyliquid impermeable.

The bodyside liner 25 may be any soft, flexible, porous sheet whichpasses fluids therethrough. The bodyside liner 25 may comprise, forexample, a nonwoven web or sheet of wet strength tissue paper, aspunbonded, meltblown or bonded-carded web composed of synthetic polymerfilaments, such as polypropylene, polyethylene, polyesters or the like,or a web of natural polymer filaments such as rayon or cotton. Thebodyside liner 25 has a pore size that readily allows the passagetherethrough of liquids, such as urine and other body exudates. Theliner 25 may be selectively embossed or perforated with discrete slitsor holes extending therethrough. Optionally, the web or sheet may betreated with a surfactant to aid in liquid transfer. One preferredbodyside liner material is a wettable spunbonded polypropylene having abasis weight of 0.7 ounces per square yard. Such material may beproduced by the methods and apparatus described in U.S. Pat. Nos.4,340,563 and 4,405,297 to Appel et al., which are incorporated hereinby reference.

The shell 22 has a front waist section 27, an opposite back waistsection 28, and a crotch area 29 (FIG. 1) which is generally locatedintermediate the front and back waist sections 27 and 28. The shell 22also has a pair of side sections 30 and 31 laterally outward of thecrotch area 29 and generally between the front and back waist sections27 and 28. The crotch area 29 is preferably narrower than the front andback waist sections 27 and 28. The shape of the side sections 30 and 31gives the shell 22 an hourglass or I shape and defines front ears 32aand 32b, which form part of the front waist section 27, and back ears32c and 32d, which form part of the back waist section 28. Each of thefront ears 32a and 32b and back ears 32c and 32d extend oppositely alongthe lateral cross-direction of the diaper 20. The front ears need not bethe same size as the back ears.

In several locations, the disposable diaper 20 may include elasticmembers to conform the shape of the diaper to the wearer and minimizethe potential for leakage. With additional reference to FIGS. 3 and 4,for example, the disposable diaper 20 includes elongated leg elasticmembers 33 positioned between the backing sheet 24 and the bodysideliner 25. The leg elastic members 33, which are located in the crotcharea 29 and extend to the front and back waist sections 27 and 28, arespaced slightly inward from the edges of the side sections 30 and 31.The leg elastic members 33 may be substantially straight, as illustratedmost clearly in FIG. 3, or may be partly or fully curved (not shown).Using ultrasonic bonds, adhesives or other suitable means, the legelastic members 33 are attached to the backing sheet 24, the bodysideliner 25, or preferably both, in an extended condition. The leg elasticmembers 33 function to draw the side sections 30 and 31 of the diaper 20to the legs of the wearer and form a seal therewith.

One preferred material for the leg elastic member 33 is a dry-spuncoalesced multifilament elastomeric thread sold under the tradenameLYCRA and available from I.E. Du Pont de Nemours and Company.Alternately, the leg elastic members 33 may be formed of other typicalelastics utilized in the diaper-making art, such as a thin ribbon ofnatural rubber. Elasticity could also be imparted to the side sectionsby extruding a hot melt elastomeric adhesive between the backing sheet24 and the bodyside liner 25. Other suitable gathering means for theside sections 30 and 31 of the diaper 20 are disclosed in U.S. Pat. Nos.4,938,754 to Mesek and 4,388,075 to Mesek et al.

The disposable diaper 20 may also include waist elastic members 34(FIGS. 3 and 5) in the front and back waist sections 27 and 28 of theshell 22. The waist elastic members 34 extend longitudinally in atransverse or lateral direction relative to the longitudinal axis of thediaper 20. The elastic members 34 are positioned generally between theears 32 of the front and back waist sections 27 and 28. Most preferably,the waist elastic members 34 are positioned between the backing sheet 24and the bodyside liner 25 and secured in an extended condition to boththe backing sheet and the bodyside liner, using ultrasonic bonds,adhesives or other suitable means.

The waist elastic member 34 may be formed of the same materials as theleg elastic members 33. One particularly preferred waist elastic member34, which is produced by the methods and apparatus disclosed in U.S.Pat. No. 4,657,802 to Morman and incorporated herein by reference, is astretch-bonded nonwoven laminate containing a spunbond polypropyleneouter facing that is bonded to an elastic meltblown core. Alternatematerials useful for the waist elastic members 34 are disclosed in U.S.Pat. Nos. 4,861,652 and 4,916,005 to Lippert et al.

To enhance the containment and absorption of urine and other bodyexudates, the disposable diaper 20 preferably includes a pair ofcontainment flaps 36 and 37. The flaps 36 and 37 extend longitudinallybetween the front and back waist sections 27 and 28 of the shell 22. Theflaps 36 and 37 are positioned slightly inboard or inward of the edgesof the respective side sections 30 and 31 and leg elastic members 33.Containment flaps as incorporated in the absorbent articles of thepresent invention are disclosed in U.S. Pat. Nos. 4,704,116 and4,846,823 to Enloe, which are incorporated herein by reference to theextent that they are consistent herewith.

The containment flaps 36 and 37 can be attached to or formed from thebodyside liner 25. If the containment flaps 36 and 37 are attached tothe bodyside liner 25, the flaps 36 and 37 may be formed of a materialthat is different than the material used for the bodyside liner. Thematerial for the containment flaps 36 and 37 may be substantially liquidpervious or impervious. One particularly preferred material for thecontainment flaps 36 and 37 is a wettable polypropylene spunbond havinga basis weight of 0.8 ounces per square yard and being random laid andbonded in a cross-hatched formation.

As illustrated best in FIG. 4, each containment flap 36 and 37 may beformed as a folded, elongated strip of material. The folded edges of thestrip of material form a base 38, which may be sealed to the bodysideliner 25 using a continuous ultrasonic bond, a continuous strip ofadhesive, a series of spotbonds, or other suitable means.

Each containment flap 36 and 37 includes a pair of elastic members 40that are positioned within the folds of the containment flap material,remote from the base 38 of the flap. As shown in FIG. 4, the elasticmembers 40 are individual strands of elastic material. The illustratedembodiment includes two elastic members 40 for each containment flap,although the particular number of strands employed for each containmentflap, and the type of elastic material, may vary. Each elastic member40, for instance, may be a thin ribbon of elastic material or severalstrands of elastic string. Most preferably, each elastic member 40 is adry-spun, coalesced multifilament elastomeric thread sold under thetradename LYCRA and available from I.E. Du Pont de Nemours and Company.

The longitudinal ends 41 (FIG. 3) of each containment flap 36 and 37 arelocated at the longitudinal ends of the diaper 20, at the front and backwaist sections 27 and 28. The ends 41 of the containment flaps 36 and 37are preferably laid down on the bodyside liner 25, with the elasticmembers 40 positioned inboard or inward of the bases 38. The ends 41 ofthe containment flaps 36 and 37 are then bonded to the bodyside liner 25by ultrasonic bonds, adhesives or other suitable means, causing thecontainment flaps to bow slightly upward and inward (see FIGS. 1, 2, and4) toward the crotch area 29 of the diaper. The containment flaps 36 and37 tend to contain solid fecal material and increase resistance toleakage of urine and fluidic fecal material. Optionally, the elasticmembers 40 could be attached directly to the bodyside liner 25 (notshown).

The diaper 20 is in its fully extended condition as shown in FIG. 3 onlyduring the manufacturing process when a series of diapers are attachedto each other in a continuous strip. When this continuous strip is cutto form individual diapers, the leg elastic members 33, the waistelastic members 34, and the containment flap elastic members 40 aresubstantially relieved of their tension and contract so that the diaperassumes a shape as illustrated in FIG. 1. The elastic members improveboth the fit and the performance of the diaper 20.

Refastenable tape members 42 (FIGS. 1-3) are operably connected to theback ears 32c and 32d of the diaper 20. Each tape member 42 includes afastening strip that may be releasably attached to a tape landing pad 43(FIGS. 3 and 5). The landing pad 43 is fixed by adhesive or othersuitable means to the surface of the backing sheet 24 that is remotefrom the bodyside liner 25. The tape members 42 and the landing pad 43are positioned so that the fastening strips may be attached to thelanding pad 43 when the diaper 20 is secured on a baby. The tape members42 and the landing pad 43 may be formed of a polypropylene film and maybe constructed in a manner as disclosed in U.S. Pat. No. 4,753,649 toPazdernik, which is incorporated herein by reference. Other suitablefastening devices, such as hooks, snaps, cohesive strips and the like,could be used in place of the tape members 42 and the landing pad 43.

The secondary absorbent layer 26 (see FIGS. 3-5) includes a secondaryabsorbent body 44, which is preferably an air-formed batt of cellulosicfibers (i.e., wood pulp fluff). One preferred type of wood pulp fluff,which is available under the trade designation CR2054 fromKimberly-Clark Corporation of Neenah, Wis., is a bleached, highlyabsorbent sulphate wood pulp containing softwood fibers. Optionally, thesecondary absorbent body 44 could comprise a coform material composed ofa mixture of cellulosic fibers and synthetic polymer fibers. Forexample, the coform material may comprise an airlaid blend of cellulosicwood fibers and meltblown polyolefin fibers, such as polyethylene orpolypropylene fibers.

The secondary absorbent body 44 may also include compounds to increasethe absorbency of the body, such as an effective amount of organic orinorganic high-absorbency materials. For example, the secondaryabsorbent body 44 can include 0-95 weight percent high-absorbencymaterial, and preferably includes 0-20 weight percent high-absorbencymaterials. Suitable inorganic high-absorbency materials include, forexample, absorbent clays and silica gels. Organic high-absorbencymaterials can include natural materials, such as pectin, guar gum andpeat moss, as well as synthetic materials, such as synthetic hydrogelpolymers. Such hydrogel polymers may include, for example,carboxymethylcellulose, alkali metal salts of polyacrylic acids,polyacrylamides, polyvinyl alcohol, ethylene maleic anhydridecopolymers, polyvinyl ethers, hydroxpropyl cellulose, polyvinylmorpholinone, polymers and copolymers of vinyl sulfonic acid,polyacrylates, polyacylamides, polyvinyl pyridine and the like. Othersuitable polymers can include hydrolyzed acrylonitrile grafted starch,acrylic acid grafted starch, and isobutylene maleic anhydridecopolymers, and mixtures thereof. The hydrogel polymers are preferablysufficiently cross-linked to render the materials substantiallywater-insoluble. Cross-linking may, for example, be by irradiation or bycovalent, ionic, van der Waals, or hydrogen bonding. Suitable materialsare available from various commercial vendors, such as Dow ChemicalCompany, Celanese Corporation, and Allied-Colloid. Typically, thehigh-absorbency material is capable of absorbing at least about 15 timesits weight in water, and preferably is capable of absorbing more thanabout 25 times its weight in water.

The high-absorbency materials may also be biodegradable high-absorbencymaterials. For example, the materials may be based on potato starch orother degradable substances. Suitable biodegradable high-absorbencymaterials are identified as Foxorb HR and Foxorb 15 and are availablefrom Avebe b.a. of Foxhol, Holland.

The high-absorbency material can be distributed or otherwiseincorporated into the secondary absorbent body 44 employing varioustechniques. For example, the high-absorbency material can besubstantially uniformly distributed among the fibers comprising theabsorbent body. The materials can also be nonuniformly distributedwithin the absorbent body fibers to form a generally continuous gradientwith either an increasing or decreasing concentration of high-absorbencymaterial, as determined by observing the concentration moving inwardfrom the backing sheet 24. Alternatively, the high-absorbency materialcan comprise a discrete layer separate from the fibrous material of thesecondary absorbent body 44, or can comprise a discrete layer integralwith the absorbent body 44.

The periphery of the secondary absorbent body 44 is preferably althoughnot necessarily formed in an hourglass or I shape similar to the shapeof the backing sheet 24 and the bodyside liner 25. The overall size ofthe secondary absorbent body 44 is smaller than the backing sheet 24 andthe bodyside liner 25, so that the backing sheet and the bodyside linerextend past the secondary absorbent body. Along their peripheries, thebacking sheet 24 and bodyside liner 25 are bonded together usingadhesives, ultrasonic bonds or other suitable means. The secondaryabsorbent body 44 is formed with a front section 45 and an opposite backsection 46 (FIGS. 3 and 5). The secondary body 44 is positioned in theshell 22 so that the front section 45 is in the front waist section 27of the shell 22 and the back section 46 is in the back waist section 28of the shell.

Between its front and back sections 45 and 46, the secondary absorbentbody 44 is formed with a pocket 47, that is preferably although notnecessarily rectangular in shape. The pocket 47 is a central opening inthe body 44, but may alternately be a region of the secondary absorbentbody that has a lower basis weight, or is formed or compressed to bethinner, than the surrounding areas. If the pocket 47 is an opening inthe secondary absorbent body 44, the opening may be formed in the fluffforming chamber, by die stamping, or other suitable means. The pocket 47extends longitudinally toward the front and back sections 45 and 46 ofthe secondary absorbent body 44, and is centered between the sides ofthe body 44 and the side sections 30 and 31 of the diaper 20.Preferably, the pocket 47 is located in the region of the diaper 20 withthe highest urine loading potential, which is slightly foreword of thelongitudinal and transverse center of the diaper 20. Thus, the pocket 47is preferably offset toward the front section 45 of the secondaryabsorbent body 44. A leading edge 48 of the pocket 47 is locatedslightly inward of the longitudinal end of the absorbent body 44 in thefront section 45. An opposite trailing edge 49 of the pocket 47 islocated generally intermediate the crotch area 29 and the longitudinalend of the absorbent body 44 in the back section 46 (see FIGS. 2, 3 and5). In this way, the pocket 47 is positioned generally in the crotcharea 29 and the area between the crotch 29 and the front waist section27 of the diaper 20.

The secondary absorbent layer 26 also includes two wrapping sheets 50(FIGS. 4 and 5) which cover the top and bottom surfaces of she secondaryabsorbent body 44 and extend into the pocket 47. The wrapping sheets 50help maintain the integrity of the secondary absorbent pad 44 andcontain the wood pulp fluff and any high-absorbency materials. Thesheets 50 may for example comprise a wet-strength cellulosic material,such as a single-ply creped wadding.

The shown embodiment of the absorbent insert pad 21 is generallyrectangular in shape and sized to reside within the pocket 47 (see FIGS.4 and 5). The insert pad 21 includes an absorbent material 52, which mayinclude wood pulp fluff and high-absorbency materials, as describedpreviously. The insert pad 21 preferably although not necessarilyincludes less than about 80 weight percent of wood pulp fluff and atleast about 20 weight percent of high-absorbency materials. Mostpreferably, the insert pad 21 contains less than about 50 weight percentof wood pulp fluff and at least about 50 weight percent ofhigh-absorbency materials. Where high-absorbency materials areincorporated into the insert pad 21, the materials may be distributed orotherwise incorporated into the pad in a substantially uniform or anonuniform distribution, employing a variety of techniques, aspreviously noted. The absorbent material 52 may for example have adensity from about 0.05 to about 0.3 grams per cubic centimeter and abasis weight from about 50 to about 700 grams per square meter.

The absorbent material 52 is preferably wrapped in a flushable,dispersible carrier sheet 53. The carrier sheet 53 may comprise alow-wet-strength cellulosic tissue. Alternately, the carrier sheet 53can comprise a nonwoven material such as a rayon carded web that isbonded with polyvinyl alcohol. One such material, is available under thetrade designation PRK 20 from Bonded Fiber Fabrics of Bridgewater,Somerset, England. This material has been evaluated and found to havetensile strengths in the machine direction of approximately 7,650 grams(dry) and 371 grams (wet) and in the transverse direction ofapproximately 838 grams (dry) and 19 grams (wet).

The ends of the carrier sheet 53 may be folded onto themselves andbonded using sonic bonds, adhesives, or other suitable means to retainthe absorbent material 52 within the carrier sheet. More preferably, theends of the carrier sheet 53 are bonded with a time sensitive binderthat will break down rapidly after being deposited in toilet bowl water.For example, the ends of the carrier sheet 53 may be bonded with apolyvinyl alcohol-based adhesive.

The longitudinally-extending sides of the carrier sheet 53 overlapslightly (see FIG. 4), and are preferably unbonded. These overlappingsides of the carrier sheet 53 allow absorbent material 52 to escape fromwithin the carrier sheet once the insert pad 21 has been removed fromthe shell 22 and deposited in a toilet. Optionally, the carrier sheet 53could be formed with slits or other openings therein. As another option,the absorbent material 52 could be covered by upper and lower carriersheets (not shown) that are sealed along their ends, sides, or both.Still optionally, a lower carrier sheet (not shown) could cover onesurface of the absorbent material and an upper carrier sheet (not shown)could cover the opposite surface, the ends, and the sides of theabsorbent material. The periphery of the upper carrier sheet couldoverlap somewhat with the periphery of the lower sheet, where theperipheries of the two sheets could be bonded together. These optionaldesigns for the carrier sheet 53 are advantageous in that the uppercarrier sheet may be positioned toward the wearer and be formed of amaterial with a higher wet tensile strength than the lower carriersheet. The upper sheet will thereby provide considerable durabilityduring use while the lower sheet, formed with substantially no chemicalsto add wet tensile strength, will disperse more readily when exposed totoilet bowl water.

The absorbent insert pad 21 is positioned against the bodyside liner 25so as to be located generally within the pocket 47. Thus, at least aportion of the insert pad 21 is positioned in the space defined withinthe inside edges or walls of the secondary absorbent body 44, includingthe leading and trailing edges 48 and 49, that form the pocket. Thewhole insert pad 21 need not completely reside within the pocket 47. Theinsert pad 21 preferably although not necessarily has a thicknessbetween about 0.06 inch and about 0.45 inch. The overlapping sides ofthe carrier sheet 53 are preferably positioned toward and adjacent thebodyside liner 25.

The cover 23 is used to retain the absorbent insert pad 21 within thepocket 47. The cover 23 comprises an upper insert liner 56 and a lowertransfer layer 57 that are substantially coterminous and in facingrelationship (see FIGS. 4 and 5). The insert liner 56 may be formed ofthe same material as the bodyside liner 25 and is preferably asubstantially fluid pervious material such as an apertured, spunbondedpolypropylene. The transfer layer 57 is formed of a material to provideadequate transfer of fluids and enhance diaper dryness, and may beformed as disclosed in U.S. Pat. No. 4,798,603, to Meyer et al. which isincorporated herein by reference to the extent that it is consistentherewith. Preferably, the transfer layer 57 comprises a wettablespunbonded material formed of continuous polypropylene filaments andhaving a basis weight of 1.0 ounce per square yard. The insert liner 56and the transfer layer 57 are bonded together, preferably along theirperimeters using ultrasonic bonds, adhesives or other suitable means.Optionally, the cover 23 could be formed of only a single layer ofmaterial, or formed of a flushable material and discarded into thetoilet along with the insert pad 21.

The cover 23 is generally although not necessarily rectangular in shapeand, as shown best in FIG. 3, is somewhat longer and wider than thedimensions of the pocket 47. The cover 23 has a recessed edge 59, anopposite exposed edge 60, and longitudinal sides 61 extending betweenthe recessed and the exposed edges 59 and 60. As shown in FIG. 5, therecessed edge 59 is positioned rearward of the trailing edge 49 of thepocket 47, and the exposed edge 60 is positioned forward of the leadingedge 48 of the pocket. Both the recessed edge 59 and the exposed edge 60are positioned above the secondary absorbent body 44. As shown in FIG.4, the sides 61 of the cover 23 are positioned outward of the pocket 47,over the secondary absorbent body 44. The width of the cover 23 ispreferably such that the cover fits between the base portions 38 of thecontainment flaps 36 and 37. Optionally, the containment flaps 36 and 37could be partially or completely attached to the cover 23 inboard of thesides 61, rather than being attached to the bodyside liner 25.

The periphery of the cover 23 is releasably attached to the diaper 20 bypeelable bonds 63 (FIGS. 4 and 5) that join the transfer layer 57 andthe bodyside liner 25. The bonds 63 are situated near the periphery ofthe cover 23 and above the secondary absorbent body 44. Thus, thepeelable bonds 63 releasably attach the cover 23 to the liner 25 at alocation immediately outward from and adjacent to the pocket 47. Thepeelable bonds 63 may be ultrasonic bonds, adhesive bonds, or othersuitable releasable bonds.

The exposed edge 60 of the cover 23 is formed by the transfer layer 57,which extends a short distance past the front edge of the insert liner56 (see FIG. 5). Alternately, the exposed edge 60 could be formed by aportion of the transfer layer 57 and the insert liner 56, or a portionof the insert liner alone. The peelable bonds 63 at the front of thecover 23 are located slightly inward of the exposed edge 60, so that theuser may easily grasp the exposed edge to remove the cover. The exposededge 60 is generally rounded (see FIGS. 1-3), and may optionally includea finger-sized aperture (not shown) to assist in removing the cover 23from the remainder of the diaper 20.

In use, the disposable diaper 20 is secured to the baby using the tapemembers 42. The waist elastic members 34 and the leg elastic members 33aid in fitting the particular diaper 20 to the individual baby. Thewaist elastic members 34, the leg elastic members 33, and theelasticized containment flaps 36 and 37 limit leakage by containingurine and fecal material.

With a diaper 20 constructed in accordance with the present invention,urine is principally absorbed by, and contained within, the absorbentinsert pad 21. The urine initially contacts the cover 23 where itquickly passes through the upper insert liner 56 to the transfer layer57. The transfer layer 57 functions to remove moisture from the insertliner 56 and promote movement of liquids into the absorbent insert pad21. The urine passes substantially through the carrier sheet 53 and isabsorbed by the absorbent material 52 of the insert pad 21. Thecontainment flaps 36 and 37 increase the effectiveness of the insert pad21 by retarding the lateral movement of urine and other fluidic materialaway from the insert pad. Thus, the insert pad 21 functions as theprimary absorbent for the diaper 20.

In the case of a large insult, urine and other fluidic substances maypass through the bodyside liner 25 and into the secondary absorbentlayer 26. In that case, liquid may pass substantially through thewrapping sheets 50 to be absorbed by the secondary absorbent body 44.The positioning of the absorbent insert pad 21 in the region of thediaper 20 with the highest urine loading potential, however, causes amajority of the urine to be absorbed by the insert pad.

The disposable diaper 20 is designed for single-use applications. Thediaper 20 is also designed so that the absorbent insert pad 21 can beremoved from the diaper after use and discarded into a toilet bowl. Theabsorbent insert pad 21 may be allowed to reside within the bowl waterfor a brief period to become substantially saturated or begin todisperse. The insert pad 21 may then simply and conveniently be flusheddown any toilet that is connected to a holding tank, a municipal sewer,or other municipal wastewater treatment system. Where the insert pad 21is formed of wood pulp fluff or biodegradable high-absorbency materials,the pad may also be flushed in toilets connected to other types ofresidential wastewater treatment systems.

One method of removing the absorbent insert pad 21 after use isillustrated in FIGS. 6 and 7. With the diaper 20 in a folded positionsuch that the front waist section 27 is positioned near the back waistsection 28 (not shown), the parent grasps the front waist section 27with one hand and grasps the back waist section 28 and the exposed edge60 of the cover 23 with the other hand. The parent then pulls the frontwaist section 27 away from the back waist section 28 and the exposededge 60, thereby breaking the peelable bonds 63 and exposing theabsorbent insert pad 21 (see FIG. 6). When the cover 23 has been pulledback a sufficient distance to expose a majority of the pocket 47 and theinsert pad 21, the diaper 20 may be inverted to allow the absorbentinsert pad 21 to fall by gravity into a toilet 66 (see FIG. 7).

As will be appreciated, a diaper 20 embodying the present inventionprovides for extremely easy removal of the flushable insert pad 21. Theparent need not contact the absorbent insert pad 21 directly, and thusthe parent's hands do not become soiled when disposing of the insert pad21. The shell 22 and the cover 23, which remain after removing theabsorbent insert pad 21, may be stored for subsequent transport to asolid waste disposal site. Optionally, where appropriate facilities areavailable, the shell 22 and cover 23 may be recycled or composted.

Upon contacting the water in the toilet, the components of the absorbentinsert pad 21 begin to disperse. Additionally, where the binder used toseal the ends of the carrier sheet 53 comprises a binder that willrapidly break down in the presence of toilet bowl water, the carriersheet tends to open at its ends. This may then cause the overlapping,unbonded sides of the carrier sheet 53 to separate. Further, the woodpulp fluff and the high-absorbency materials of the absorbent material52 may absorb bowl water. The carrier sheet 53 and absorbent material 52may be flushed down the toilet. The insert pad 21 may also be allowed toreside in the bowl water prior to flushing, preferably less than twominutes.

Several other options are available to a parent using the discloseddiaper. For example, the parent can easily deposit solid fecal wastefrom the diaper 20 into the toilet, given that the parent is positionednear the toilet to dispose of the absorbent insert pad 21. Anotheroption is for the parent to completely remove the non-flushable cover 23from the shell 22. The feces adhered to the cover 23 may be rinsed inthe toilet bowl to more completely dispose of such material in thetoilet. Optionally, any dry portion of the cover 23 could be used towipe the child's bottom, prior to rinsing the cover. In all of thesescenarios, solid feces material may be removed from the diaper forflushing without any need for the parent to touch the feces or theabsorbent insert pad 21.

The hydraulic action of flushing the insert pad 21 and transporting itto a municipal wastewater treatment facility will further break down theabsorbent material 52 and carrier sheet 53 of the insert pad 21 intoindividual particles and fibers that can be accommodated by themunicipal facility. The low-wet strength carrier sheet 53 has been foundto completely break apart after several hours in a water stream. Theinsert pad 21 can also be flushed into a holding tank system or, wherethe absorbent material 52 is wood pulp fluff and biodegradablehigh-absorbency materials, into other types of residential systems.

The disposable diaper 20 of the present invention provides a significantadvantage over prior diapers which were completely sent to solid wasterefuse sites. Flushing the absorbent insert pad 21 and the fecesmaterial down the toilet reduces by about one-half the weight amountthat would normally have to be sent to a solid waste disposal facilityusing a completely non-flushable diaper. Furthermore, the components ofthe diaper that are not flushed down the toilet, such as the backingsheet 24, bodyside liner 25, secondary absorbent body 44, cover 23,containment flaps 36 and 37, elastic members 33, 34, and 40, and thetape members 42, may be recycled or composted if such facilities arelocally available.

A second embodiment of the present invention is illustrated by diaper 80in FIG. 8, where components similar to those previously described havethe same reference numeral. The flushable absorbent insert pad 21 inthis embodiment employs a carrier sheet 81 that is formed at one end ofthe pad with a tab 82. When the insert pad 21 is positioned within thepocket 47 with the tab 82 toward the front waist section 27, the tabresides on the bodyside liner 25 at a location above the front section45 of the secondary absorbent body 44. The tab 82 projects from thepocket 47 and is positioned generally beneath the exposed edge 60 of thecover 23. Optionally, the tab 82 could project past the exposed edge 60.The recessed edge 59 and the sides 61 of the cover 23 are releasablysecured to the bodyside liner 25, while the exposed edge 60 ispreferably not secured to either the bodyside liner 25 or the carriersheet 81. Alternately, the exposed edge 60 may be lightly, releasablybonded to the bodyside liner 25 using sonic bonds, adhesives, or othersuitable means.

To remove the flushable insert pad 21 from this diaper 80, the parentpulls the exposed edge 60 of the cover 23 away from the front waistsection 27 to break the peelable bonds 63 and expose a majority of theinsert pad. In doing so, the tab 82 of the carrier sheet 81 is exposedto view. The parent may then grasp the tab 82 and pull the absorbentinsert pad 21 from the pocket 47. To assist in removing the insert pad21, the tab could optionally be formed with a finger-sized aperture (notshown). After removing the insert pad 21 from the pocket 47, the insertpad may then be placed in a toilet bowl and subsequently flushed, aspreviously described. Additionally, the parent may deposit any solidfecal material in the toilet, and remove and rinse the cover 23 in thetoilet. The tab 82 provides a convenient means for the parent to controlthe position of the insert pad 21 prior to flushing, while stillminimizing the parent's exposure to bodily waste.

A third embodiment of the invention is illustrated by the diaper 90shown in FIGS. 9 and 10. In this embodiment, the diaper 90 comprises ashell 22 that includes a bodyside liner 25 and a backing sheet 24, butdoes not include a secondary absorbent layer (such as layer 26 in FIGS.3-5) between the bodyside liner and the backing sheet. The bodysideliner 25 is secured directly to the backing sheet 24, in face-to-face,intimate contact, using adhesives or other suitable means.

The diaper 90 of FIGS. 9 and 10 further includes leg elastic members 33,waist elastic members 34, and elasticized containment flaps 36 and 37 tocontain urine and fecal material. An absorbent insert pad 91 of thediaper 90 is formed of an absorbent material 52 that is wrapped in acarrier sheet 53. The width of the absorbent insert pad 91 isappropriate to fit between the containment flaps 36 and 37, and thelength of the pad is appropriate to fit generally between the front andback waist elastic members 34, such as to the longitudinal end areas,designated by arrows 96 and 97 in FIG. 9.

The absorbent insert pad 91 is releasably retained against the bodysideliner 25 by a cover 92 that comprises an upper insert liner 56 and alower transfer layer 57. Optionally, the cover 92 could comprise asingle layer or have an upper transfer layer and a lower insert liner.The cover 92 has an exposed front edge 93 and an opposite exposed backedge 94, with sides 61 extending between the exposed front and backexposed edges. The corners 95 between the sides 61 and the front andback exposed edges 93 and 94 are recessed. The cover 92 is sized so thatthe exposed front edge 93 lies adjacent the front waist section 27 nearthe front waist elastic member 34, and the exposed back edge 94 liesadjacent the back waist section 28 near the back waist elastic member34.

The sides 61 of the cover 92 extend over the longitudinal sides of theabsorbent insert pad 91, and are releasably secured to the bodysideliner 25 by peelable bonds 63. The sides 61 of the cover 92 are locatedinward of the containment flaps 36 and 37. The recessed corners 95 causethe cover 92 to avoid the containment flap ends 41, which are foldedtoward the central, longitudinal axis of the diaper and secured to thebodyside liner 25. As an alternative (not shown), the containment flaps36 and 37 could be formed from, or attached to, the periphery of thecover 92, rather than being formed from, or attached to, the bodysideliner 25.

Compared to the embodiments depicted in FIGS. 1-8 which may be said toutilize a partial-length flushable insert, the diaper 90 of FIGS. 9 and10 provides a full-length, flushable absorbent insert pad 91. Thepartial-length insert pad may have a length dimension between about 8and about 101/2 inches, for example, while the full-length insert padmay have a length dimension between about 101/2 and about 15 inches, forexample. Both the partial-length and the full-length pads may preferablyhave a width dimension between about 2 and about 41/2 inches.Additionally, because this embodiment does not employ a secondaryabsorbent layer, all of the absorbent material 52 of the diaper iscontained in the absorbent insert pad 91. Thus, all of the absorbentmaterial 52 of this diaper 90 can be emptied into and subsequentlyflushed down a toilet.

To dispose of the full-length insert pad 91, the cover 92 is at leastpartially separated from the diaper shell 22 by pulling on either theexposed front edge 93 or the exposed back edge 94 to break the peelablebonds 63. The parent thus has the option of touching either the frontedge 93 or the back edge 94, whichever is drier or more convenient.After removing the cover 92 a distance sufficient to expose a majorityof the insert pad 91, the diaper 90 may be inverted to allow theabsorbent insert pad 91 to fall by gravity into a toilet. The absorbentinsert pad 91 may then be flushed, or may be allowed to reside in thebowl water prior to flushing, preferably less than two minutes.

The larger absorbent insert pad 91 of this embodiment enables a greaterpercentage by weight of the diaper to be disposed of by flushing ratherthan delivery to a solid waste disposal facility. In fact, flushing thefull-length absorbent insert pad 91 and the feces material down thetoilet reduces by substantially more than half the weight amount thatwould normally have to be sent to a solid waste disposal facility usinga completely non-flushable diaper. Additionally, the cover 92 may befully separated from the bodyside liner 25 and rinsed in the toilet bowlto more completely dispose of any solid fecal material.

A fourth embodiment of the present invention is illustrated by thediaper 110 of FIG. 11. A shell 22 of the diaper includes a secondaryabsorbent body 44 having a pocket 47 that extends substantially thefull-length of the diaper. A flushable, absorbent insert pad 91 of thediaper is sized to reside within the pocket 47. The insert pad 91comprises a carrier sheet 53 that contains an absorbent material 52. Thecarrier sheet 53 is formed with a rounded end 111 that is locatedadjacent the front waist section 27, but alternately could be locatednear the back waist section 28. The rounded end 111 includes afinger-sized aperture 112 therethrough.

The full-length absorbent insert pad 91 is retained within the pocket 47(not shown in FIG. 11) by a cover 92. The longitudinally-extending sides61 of the cover 92 are positioned outboard or outward of the pocket 47and between the base portions 38 of the containment flaps 36 and 37.Optionally, the containment flaps 36 and 37 could be formed on the cover92. The sides 61 are releasably attached to the bodyside liner 25 bypeelable bonds 63. The rounded end 111 of the carrier sheet 53 protrudesfrom beneath an exposed front edge 93 of the cover 92. Optionally, therounded end 111 may be located beneath the exposed front edge 93 so thatit becomes visible only upon lifting the front edge.

Once the diaper 110 has been soiled, the absorbent insert pad 91 may beremoved from the pocket 77 for disposal into a toilet. This may beaccomplished by pulling on the rounded end 111, using the aperture 112if desired, while holding the opposite waist section of the diaper, assuggested by FIG. 11. The carrier sheet 53 may be reinforced withadditional layers of a flushable, dispersible material at the roundedend 111 to provide added strength for pulling the insert pad 91 from thepocket 77. Preferably, the carrier sheet 53 has a wet tensile strengthin the machine direction between about 100 grams and about 1,000 grams,and more preferably between about 300 grams and about 500 grams. Thisdiaper 110 allows the parent to control the position of the insert pad91 prior to placing the insert pad 91 in the toilet, while stillminimizing the parent's contact with soiled portions of the diaper. Aswith other embodiments, the cover 92 may conveniently be removed fromthe shell 22 for rinsing in the toilet bowl.

A fifth embodiment of the invention is illustrated by an especially thindiaper 120 illustrated in FIGS. 12 and 13, shown not to scale forpurposes of clarity. The diaper comprises a shell 22 having a backingsheet 24, a bodyside liner 25, and a secondary absorbent layer 26therebetween. The secondary absorbent layer 26 (FIG. 13) includes arelatively thin secondary absorbent body 44 that is covered on its topand bottom faces by wrapping sheets 50. The secondary absorbent body 44preferably comprises two elongated, C-shaped portions. The C-shapedportions are located on opposite sides of the diaper 120 and arepositioned in the ears 32 and side sections 30 and 31. The secondaryabsorbent body 44 is preferably formed principally of wood pulp fluff,but may also comprise coform material or high-absorbency materials.

A thin full-length, flushable absorbent insert pad 121 of the diaper 120is sized to reside between the containment flaps 36 and 37 and generallybetween the front and back waist elastic members 34 (not shown). Theinsert pad 121 comprises a carrier sheet 53 that is wrapped about anabsorbent material 122. The absorbent material 122 comprises twolow-wet-strength cellulosic tissue sheets 123 and three thin absorbentsheets 124. The sheets 123 and 124 are arranged with a tissue sheet 123on the top (away from the shell 22), then a thin absorbent sheet 124,then another tissue sheet, followed by two thin absorbent sheetspositioned above and located toward the bodyside liner 25. The exactnumber and arrangement of sheets may be varied. The tissue sheets 123function to distribute fluids and maintain the integrity of the thinabsorbent sheet 124. The overall thickness of the insert pad 121 ispreferably between about 0.06 inch to about 0.45 inch. For purposes ofillustration, the components of the insert pad 121 have beendisproportionately enlarged in thickness in the Figures.

The thin absorbent sheets 124 comprise high-absorbency materials andnatural or synthetic fibers, such as polymeric, rayon or wood pulpfibers. The amount of high-absorbency materials in a sheet 124 ispreferably between about 20 and about 90 weight percent, and morepreferably between about 50 and about 85 weight percent. One suitablethin absorbent sheet is a wet-formed composite structure comprising acombination of high-absorbency materials and natural or syntheticfibers. The composite structure and its method of manufacture aredescribed in a U.S. patent application Ser. No. 744,137, by Anderson etal., titled "Wet-Formed Absorbent Composite", which was filed on Aug.13, 1991 and assigned to the assignee of the present invention, andwhich is incorporated herein by reference to the extent that it isconsistent herewith. Another suitable thin absorbent sheet is adry-formed composite structure comprising a combination ofhigh-absorbency materials and natural or synthetic fibers. Thiscomposite structure and its method of manufacture are described in U.S.patent application Ser. No. 805,126, by Veith et al., titled "HighAbsorbency Composite", which was filed on Dec. 11, 1991 and assigned tothe assignee of the present invention, and which is incorporated hereinby reference to the extent that it is consistent herewith.

The absorbent insert pad 121 of FIGS. 12 and 13 is releasably held inplace against the bodyside liner 25 by a cover 125. The cover 125includes an transfer layer 57 that is attached along its sides to thebodyside liner 25 by suitable bonds 126, which may be a continuous lineor series of ultrasonic bonds, adhesive bonds or the like. The transferlayer 57 is formed with rounded corners and has exposed front and backedges 60 that are positioned adjacent the front and back waist elasticmembers 34 (not shown in FIGS. 12 and 13).

The cover 125 also includes a rectangular surge layer 127 attached tothe top of the transfer layer 57 by ultrasonic bonds, adhesives, orother suitable means. The length and width of the surge layer 127 areapproximately the same as the length and width of the absorbent insertpad 121, and the surge layer is positioned on the transfer layer 57 at alocation that corresponds to the location of the insert pad. The surgelayer 127 is formed of a material that is capable of rapidly absorbingmultiple, large volume urine insults. One suitable material is apolyester powder bonded carded web available from Bonar Fabrics underthe tradename PBCW 1021, which material has a basis weight of about 50grams per square meter. Optionally, the surge layer 127 may bepositioned beneath the transfer layer 57, or the cover 125 may be formedof a single liquid permeable material.

To facilitate removal of the absorbent insert pad 121, the transferlayer 57 has two predetermined longitudinally-extending lines ofrelative weakness, such as lines of perforations 128. The perforationlines 128 extend the complete length of the transfer layer 57. The lines128 are oriented parallel to the sides of the surge layer 127, and arelocated between the adhesive bonds 126 (FIG. 13) and the longitudinalsides of the surge layer. Optionally, the lines of relative weaknesscould be areas of the transfer layer 57 that are weakened by ultrasonicsor other suitable means.

The absorbent insert pad 121 can be removed from the shell 22 by pullingeither the front or back exposed edge 60 of the cover 125 away from theshell. This causes the transfer layer 57 to tear along the perforationlines 128, thereby exposing the absorbent insert pad 121. When amajority of the transfer layer 57 has been torn, the diaper 120 may beinverted to allow the insert pad 121 to fall by gravity into a toilet.The cover 125, including the surge layer 127 and the portion of thetransfer layer 57 between the perforation lines 128, may be fullyremoved from the shell 22 so that it can be rinsed in the toilet. Theinsert pad 121 may then be flushed in the toilet, or may be allowed toreside in the bowl water prior to flushing, preferably less than twominutes.

A sixth embodiment of the invention is illustrated by the diaper 140 inFIGS. 14 and 15, shown not to scale for purposes of clarity. This diaper140 includes a relatively thin secondary absorbent body 141 that issandwiched between the backing sheet 24 and the bodyside liner 25. Thesecondary absorbent body 141 is formed of a relatively thin absorbentmaterial, which may include wood pulp fluff, coform material, andhigh-absorbency materials. The secondary absorbent body 141 is formedwith an hourglass or I shape, and does not include a pocket as employedwith several previous embodiments disclosed herein.

A flushable, absorbent insert pad 142 of the diaper 140 comprises anabsorbent material, in the form of pair of thin absorbent sheets 124,which are wrapped in a carrier sheet 53. Two thin absorbent sheets 124are illustrated in FIGS. 14 and 15, although the number may be varied toobtain the required level of absorbent capacity. Tissue sheets (notshown) may also be employed in contact with the thin absorbent sheets tocontain the high-absorbency materials and help distribute fluids. Theends of the carrier sheet 53 may be bonded together by sonic bonds,adhesives or other suitable means to retain the thin absorbent sheets124 within the carrier sheet 53, but are preferably bonded using abinder that will rapidly break down when immersed in toilet bowl water.The absorbent insert pad 142 is a full-length pad but could optionallybe formed as a partial-length pad.

The diaper 140 includes a cover 144 having exposed front and back edges93 and 94 and longitudinally-extending sides 61 extending between thefront and back edges. The cover is formed with a top insert liner 56 anda bottom transfer layer 57, but could optionally be formed as a singlelayer or include a surge layer 127. Inboard of the longitudinal sides61, the cover 144 includes two longitudinally-extending lines ofrelative weakness in the form of lines of perforations 128 that extendthe complete length of the cover. Inboard of the perforations 128,containment flaps 36 and 37 are attached to or formed from the cover144.

The insert pad 142 is positioned on the bodyside liner 25, centeredbetween the side sections 30 and 31. In this diaper 140, the absorbentmaterial of the insert pad 142 is in substantially direct fluid contactwith the secondary absorbent body 141, whereby fluid can migrate alongthe most direct line from any given portion of the absorbent material ofthe pad 142 to the secondary absorbent body 141 without encountering asubstantially liquid impervious material, such as a portion of thebacking sheet 24. Specifically, only the carrier sheet 53 and thebodyside liner 25, which are both substantially liquid pervious,separate the absorbent material of the insert pad 142 and the secondaryabsorbent body 141.

The cover 144 is positioned over the insert pad 142 and thelongitudinally-extending sides 61 are attached to the bodyside liner 25using ultrasonic bonds, adhesives or other suitable means. Thecomponents of the diaper 140 are preferably sized so that thecontainment flaps 36 and 37 are outboard of the absorbent insert pad142.

The absorbent insert pad 142 may be removed from the diaper 140 bypulling on either the exposed front edge 93 or the exposed back edge 94of the cover 144. The cover 144 will thereby tear along the lines ofperforations 128 to expose the absorbent insert pad 142 which liesbeneath the cover. In this embodiment, the containment flaps 36 and 37remain attached to the portion of the cover 144, between the lines ofperforations 128, that is separated from the shell of the diaper.Advantageously, solid fecal waste on the cover 144 tends to be held inplace between the elastic containment flaps 36 and 37 as the cover isbeing removed. Such fecal material can then be deposited in a toilet bycompletely removing the cover 144 and rinsing it in the toilet.

This diaper 140 is also advantageous because of its relative thinness,which is attributable to the thin absorbent sheets 124 and therelatively thin secondary absorbent body 141. The diaper 140 alsoprovides manufacturing efficiencies because the secondary absorbent body141 does not need to be formed with a pocket or C-shaped portions.Furthermore, because the absorbent material 124 is in substantiallydirect fluid contact with the secondary absorbent body 141, thesecondary absorbent body can rapidly absorb liquid from the insert padbefore the insert pad becomes saturated. This enhances the performanceof the diaper 140 by attracting liquid away from the cover 144, therebykeeping it dry and comfortable. Complete direct fluid contact betweenthe absorbent material 124 and the secondary absorbent body 141 is notrequired, because relatively small pieces of liquid impervious material,such as tapes, elastics, or other materials, positioned between theabsorbent material of the insert pad 142 and the secondary absorbentbody will not substantially impede fluid movement from the insert pad142 to the secondary body.

It will be apparent to one skilled in the art that the cover 144 couldbe extended to be substantially coterminous with the backing sheet 24(not shown). In this case, the cover would function as a cover/bodysideliner. In such an article, the absorbent insert pad 142 could bepositioned beneath the cover/bodyside liner, and the cover/bodysideliner could be formed with one or more lines of relative weakness, suchas perforations 128. The insert pad 142 could be released from beneaththe cover/bodyside liner by tearing the cover/bodyside liner along thelines of relative weakness (perforations 128).

The foregoing detailed description has been for the purpose ofillustration. Thus, a number of modifications and changes may be madewithout departing from the spirit and scope of the present invention.For example, the relative size of the pocket 47 and cover 23 may bemodified to comprise a greater or lesser area of the article. Also,alternative absorbent materials may be substituted for those describedherein. Likewise, presently non-flushable components, such as the cover23, may be formed of flushable materials and discarded into the toiletwith the flushable insert pad. Further, many of the particular aspectsdescribed in relation to one embodiment may be implemented incombination with aspects of other embodiments. Such aspects include: thedesign of the secondary absorbent layer, the absorbent insert pad, orthe cover; the location of the containment flaps; and the use ofperforation lines or a partial or a full-length insert pad. Therefore,the invention should not be limited by the specific embodimentsdescribed, but only by the claims.

We claim:
 1. An absorbent article, comprising;a shell free of absorbentmaterial and formed of a bodyside liner and a substantially liquidimpervious backing sheet, the bodyside liner and the backing sheet beingbonded directly together in face-to-face intimate contact, the shelldefining a front waist section, a back waist section, and opposed firstand second sides extending between the front and back waist sections; apair of containment flaps attached to the bodyside liner, thecontainment flaps extending between the front and back waist sectionsand being positioned inward of the respective first and second sides; aninsert pad formed of a flushable absorbent material, the insert padpositioned against the bodyside liner and between the containment flaps;and a cover for releasably maintaining the insert pad in positionrelative to the bodyside liner.
 2. The absorbent article of claim 1,wherein the flushable absorbent material comprises at least about 20weight percent high-absorbency material that is adapted to absorb atleast 15 times its weight in water.
 3. The absorbent article of claim 2,wherein the flushable absorbent material comprises at least about 50weight percent high-absorbency material that is adapted to absorb atleast 15 times its weight in water.
 4. The absorbent article of claim 2,wherein the flushable absorbent material comprises at least onelow-wet-strength tissue sheet positioned adjacent at least one thinabsorbent sheet.
 5. The absorbent article of claim 1, wherein the coveris attached to the bodyside liner and the cover includes at least oneline of perforations therein.
 6. An absorbent article, comprising:ashell comprising a bodyside liner and a substantially liquid imperviousbacking sheet, the bodyside liner and the backing sheet being inface-to-face intimate contact; an insert pad positioned against thebodyside liner, the insert pad comprising a flushable absorbent materialincluding at least about 20 weight percent high-absorbency material, theflushable absorbent material wrapped in a flushable, dispersable carriersheet; a cover positioned over the insert pad, the cover having sidesreleasably attached to the bodyside liner; and a pair of containmentflaps bonded to the cover, wherein the cover comprises lines of relativeweakness and the containment flaps are positioned inboard of the linesof relative weakness.